70mm through bore is a problem.
Most 'hobby' lathes are only 1"/26mm through bore, with some of the more common modern ones only being 20mm. Even once you go into more industrial lathes, to get 3" involves getting a fairly substantial lathe.

I've spent a fair bit of time lately exploring options to upgrade from my Conect, and I'm currently looking at a Clarke CL430 and machining the bed to accept linear rails. It still does limit me to 26mm through bore, but that's more than what I need for existing items. However I'd be looking to upgrade to a 2"/50mm headstock at some point.

I could probably pick up a used/scrapped large CNC lathe for not much money, but I physically don't have the room, or the power supply for that matter, and for what I usually make would be very much overkill.

You've got to decide what you intend to make, and what concessions you're wiling to make.