Right. Your best bet would be to go for a complete bike, pop a wanted ad as said. It'll be a lot cheaper to buy a complete bike than build one up. Less faff than moving everything over as well. Ease yourself into wrenching, get a nice serviceable bike that suits your needs and maintain it yourself, get tools as you need them and don't overthink it too much. You can also make a thread asking what to look for, occasionally there's good bargains posted in the Marketplace/eBay watch section too.
https://www.retrobike.co.uk/forums/mtb-ebay-marketplace-watch.4/
And here's the wanted section:
https://www.retrobike.co.uk/forums/mtb-wanted.3/
Throwing good money after bad is never the right approach. Impel cranksets are solid and I like them a lot, but if I were I'd put the money aside and look when somrtbing pops up on here in the 150ish quid bracket. Occasionally some real bargains cheaper too. What are your needs specifically?