A new cassete, chainrings, chain, brake pads, and new shifter/brake cables/housing and tires are all wear items, can all be had for under $175 (maybe even under 150) That would be for really basic stuff, though it would be at least as good as what the bike came with.

For the front deraileur, I’d get a used one off ebay for $15. Unless something actually breaks, they basically last forever.

These prices all assume you are doing the work yourself. You may have to add money for special tools, though in my experience, basic bike tools always pay for themselves.

IF that is really all the bike needs, I would do it. I mighy even spend a little more and get some better tires than what came stock.

However, if you have not been doing maintenance on the fork, that may be near the end of its useful life. At this point it gets pretty questionable whether it is worth putting more money into the bike.