I buy and sell turntables for fun. Usually buy faulty or damaged ones and fix them. Rega, all day long.
Rega's entry deck, the P1/RP1, is not the most solidly built thing you've ever seen but as soon as you go above that the decks are very well made. On ProJect entry decks the build quality is shite and when you spend proper money, it's still shite! If you think of the cheapest way to do something, that's almost certainly what ProJect have done.
Plus the Regas sound better so no brainer really. Even the P1 sounds great for the money.
I'd look at one of Audio Technicas new carts. AT carts have always matched Rega turntables very well. Back in the day a Linn K9, which is a metal bodied AT with a nice stylus, was the go to cart for a Planar3/RB300. I actually have an old K9 on my RP10 right now and it works ridiculously well. I prefer it to all of the other carts I've tried, including a 2M Black, 540MkII and a few MC carts. If you buy the cheapest of the new metal bodied ATs you can upgrade the stylus later.
Don't get me wrong, I like Ortofon carts too. It's just a question of context. The VMS 20e MkII is one of my all time favourites, and I like the 2Ms, but I'd have an AT as long as the deck is good enough to tame it. Which your Rega is.