I wonder if Steam flatpack version would help here? https://www.omgubuntu.co.uk/2017/06/steam-now-available-flatpak

At least until the problem gets solved

Hey @kisak-valve thanks for the reply,
The reason the steamui.so won't launch is because of missing 32 bit libraries (dependencies) such as:
libXtst.so.6
libgtk-x11-2.0.so.0
libgdl_pixbuf-2.0.so.0

I tried ~sudo -apt -install "libXtst.so.6", I'm pretty sure its incorrect but this is how I tried manually installing my missing libraries from the i386 repository.

These can be seen in the attached screenshots above (I'm not sure if they appear to you, I'm new to this site so excuse my ignorance).

I checked glxinfo on my tilix terminal and it gave me this (code was too long so here's some of it), it seems just fine:

name of display: :0
display: :0  screen: 0
direct rendering: Yes
server glx vendor string: SGI
server glx version string: 1.4
server glx extensions:
    GLX_ARB_create_context, GLX_ARB_create_context_no_error, 
    GLX_ARB_create_context_profile, GLX_ARB_create_context_robustness, 
    GLX_ARB_fbconfig_float, GLX_ARB_framebuffer_sRGB, GLX_ARB_multisample, 
    GLX_EXT_create_context_es2_profile, GLX_EXT_create_context_es_profile, 
    GLX_EXT_fbconfig_packed_float, GLX_EXT_framebuffer_sRGB, 
    GLX_EXT_import_context, GLX_EXT_libglvnd, GLX_EXT_no_config_context, 
    GLX_EXT_texture_from_pixmap, GLX_EXT_visual_info, GLX_EXT_visual_rating, 
    GLX_INTEL_swap_event, GLX_MESA_copy_sub_buffer, GLX_OML_swap_method, 
    GLX_SGIS_multisample, GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, 
    GLX_SGIX_visual_select_group, GLX_SGI_make_current_read, 
    GLX_SGI_swap_control
client glx vendor string: Mesa Project and SGI
client glx version string: 1.4
client glx extensions:
    GLX_ARB_context_flush_control, GLX_ARB_create_context, 
    GLX_ARB_create_context_profile, GLX_ARB_create_context_robustness, 
    GLX_ARB_fbconfig_float, GLX_ARB_framebuffer_sRGB, 
    GLX_ARB_get_proc_address, GLX_ARB_multisample, GLX_EXT_buffer_age, 
    GLX_EXT_create_context_es2_profile, GLX_EXT_create_context_es_profile, 
    GLX_EXT_fbconfig_packed_float, GLX_EXT_framebuffer_sRGB, 
    GLX_EXT_import_context, GLX_EXT_texture_from_pixmap, GLX_EXT_visual_info, 
    GLX_EXT_visual_rating, GLX_INTEL_swap_event, GLX_MESA_copy_sub_buffer, 
    GLX_MESA_multithread_makecurrent, GLX_MESA_query_renderer, 
    GLX_MESA_swap_control, GLX_OML_swap_method, GLX_OML_sync_control, 
    GLX_SGIS_multisample, GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, 
    GLX_SGIX_visual_select_group, GLX_SGI_make_current_read, 
    GLX_SGI_swap_control, GLX_SGI_video_sync
GLX version: 1.4
GLX extensions:
    GLX_ARB_create_context, GLX_ARB_create_context_profile, 
    GLX_ARB_create_context_robustness, GLX_ARB_fbconfig_float, 
    GLX_ARB_framebuffer_sRGB, GLX_ARB_get_proc_address, GLX_ARB_multisample, 
    GLX_EXT_buffer_age, GLX_EXT_create_context_es2_profile, 
    GLX_EXT_create_context_es_profile, GLX_EXT_fbconfig_packed_float, 
    GLX_EXT_framebuffer_sRGB, GLX_EXT_import_context, 
    GLX_EXT_texture_from_pixmap, GLX_EXT_visual_info, GLX_EXT_visual_rating, 
    GLX_INTEL_swap_event, GLX_MESA_copy_sub_buffer, GLX_MESA_query_renderer, 
    GLX_MESA_swap_control, GLX_OML_swap_method, GLX_OML_sync_control, 
    GLX_SGIS_multisample, GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, 
    GLX_SGIX_visual_select_group, GLX_SGI_make_current_read, 
    GLX_SGI_swap_control, GLX_SGI_video_sync
Extended renderer info (GLX_MESA_query_renderer):
    Vendor: Intel Open Source Technology Center (0x8086)
    Device: Mesa DRI Intel(R) UHD Graphics 620 (Kabylake GT2)  (0x5917)
    Version: 18.2.2
    Accelerated: yes
    Video memory: 3072MB
    Unified memory: yes
    Preferred profile: core (0x1)
    Max core profile version: 4.5
    Max compat profile version: 3.0
    Max GLES1 profile version: 1.1
    Max GLES[23] profile version: 3.2

I attempted doing a simple test:

~$ glxgears
381 frames in 5.0 seconds = 75.983 FPS
300 frames in 5.0 seconds = 59.973 FPS
300 frames in 5.0 seconds = 59.973 FPS
300 frames in 5.0 seconds = 59.975 FPS
300 frames in 5.0 seconds = 59.974 FPS
300 frames in 5.0 seconds = 59.977 FPS
300 frames in 5.0 seconds = 59.968 FPS
300 frames in 5.0 seconds = 59.976 FPS
300 frames in 5.0 seconds = 59.977 FPS
300 frames in 5.0 seconds = 59.967 FPS
300 frames in 5.0 seconds = 59.971 FPS
300 frames in 5.0 seconds = 59.976 FPS
300 frames in 5.0 seconds = 59.965 FPS
300 frames in 5.0 seconds = 59.978 FPS
300 frames in 5.0 seconds = 59.979 FPS
300 frames in 5.0 seconds = 59.971 FPS

and then closed the gears animation which gave this:

XIO:  fatal IO error 11 (Resource temporarily unavailable) on X server ":0"
     after 4968 requests (43 known processed) with 0 events remaining.

I wonder if Steam flatpack version would help here? https://www.omgubuntu.co.uk/2017/06/steam-now-available-flatpak

At least until the problem gets solved

Thank you, I'll try that as well.

I've got a feeling that sudo -apt -install "libXtst.so.6" is going to give you 64 bit variants and you're also testing with 64bit glxinfo. I'd explicitly ask apt to give both 32 bit and 64 bit mesa with something like sudo apt install libgl1-mesa-glx libgl1-mesa-glx:i386 mesa-vulkan-drivers mesa-vulkan-drivers:i386

You can check which variant of glxinfo you have installed with apt policy mesa-utils mesa-utils:i386.

Thank you, I have downloaded the flatpack steam client (as per @byte1024's suggestion) and its so far fully functional, would you recommend for me to continue using it? I fear that it maybe untrusted, I've seen recent articles on how Flatpack can be a security nightmare for Linux.

Otherwise I will delete it and redownload the official steam client, continuing with the possible solutions you have provided.

Thanks in advance.