Most hi-fi equipment outputs at a similar “line level” so CD players, radios, cassettes etc can all be plugged into one of the line level inputs on your amp. Record players output the signal at a much lower level so need a bit of a helping hand getting it to “line level”. This is what a phono stage is. If an amp has a phono stage it will look like all the other inputs, but it is not the same internally. If your amp does not have a phono stage there are good separate units that can plug into your amp, some of which are not very big either.
As for the deck itself, you are wandering into nerdy geeky territory where everyone will have an opinion…and everyone else will be wrong 😉
The Project decks are good value and I think Richer Sounds may still sell them if you don’t want to buy S/H but don’t want to venture into Linn price brackets. But your ears will know best, so try a few auditions. Most good shops should let you take your kit in.