Working on your own engine gives you a level of understanding that cannot otherwise be obtained. It's like writing your own OS. This is very much a worthwhile endeavour. People should be encouraged to write their own crap, even if they don't end up using it on the job or whatever (whoever the fuck said this was the only metric for deciding what to work on?) because of the level of insight it provides.
Generic engines like UE5 and Unity break down both in terms of functionality and performance the moment you do something they are not intended to do. They are also an overkill for a project of the scale shared here. From an engineering perspective, it's absolutely ridiculous to use an engine for this project.
So please stop parroting this nonsense. Use your goddamn brain to form opinions. There isn't an off-the-shelf engine for that.