Newbie Used Help, Definitive Technology

I've been scouring FBMP for a while looking for a 5.1 setup. I am completely new to this scene, and looking to replace a terrible TCL Q5 soundbar + surround 5.1 setup. Its horrible.

I found a set of Definitive Technology Mythos 5 piece, with 2 Mythos 5, 2 Mythos Gem and a Mythos 7. Posted for around $400, which is basically exactly the budget I had in mind. No sub, but I can stretch the budget to pick one up separately. I already have a receiver.

This is the first find that I've googled and haven't read countless 'those are dogshit' posts, but I wanted to check here with the experts. Is this good? I am not an audiophile, I am okay with being blissfully ignorant that there is much better out there, but I do really want a solid upgrade over the terrible setup I have now. Use case is 90% TV/Movies, with some occasional music. Again, not an audiophile so I don't know what 'good' is, nor do I really want to (can't afford to), but I want something good that won't disappoint and will last a long time as a 'solid' budget setup.