I was gonna say, I tried it a couple months ago and I’m pretty sure it hadn’t been changed since when I was using it in like 2012. I thought a theme might help so I checked out the available themes, and the “popular” ones were ones that felt like they were from back then too. Everyone remembers Firefox / Thunderbird themes from back then: frosted glass, photos of space, flames, lots of gradients, themes that look like wood for some reason, that gross red text on black-white gradient background. It was like the entire app was aesthetically trapped in the early 2010s, even the community’s themes.
All I know is that I’m in the same situation and the gmail mobile app works, so there’s something you can do.