I have the same one. It works for what I need it for, which is streaming video and reading.
When you think about it, though, that thing was very snappy to use a few years ago. What happened is that every iOS/iPadOS update got more demanding, until we ended up where we are today. People are out here blaming the hardware, but I distinctly remember this iPad being a pleasure to use not terribly long ago.
What sucks about this is that Apple doesn't seem interested in keeping alive an OS version with current security updates (and some subset of new features) that doesn't drag the whole thing to hell and make it unusably slow. I guess they have no incentive to, but it does suck.
I'll probably get another iPad Mini, but this time I'm going to stop updating at some point in the interest of prolonging its useful life.
Yeah it's definitely worsened with each OS update, for sure it's the OS demands. I wish Apple had a way of downgrading the OS.