Do any of these modern DSLRs take old Mamiya Sekor lenses?
The Pentax will but you will need an adapter. Fortunately they have been making screw mount to K-mount adapters for probably 35 years. I assume they are still making them.
I really don’t think adapters are all that good an idea unless you have a lens which is unusually sharp. They all or nearly all require manual everything.
I do have a couple of interesting high quality adapters which adapt an old Minolta MD or MC lens to Maxxum mount. They are also teleconverters. One is a 1.4X and the other is a 2X. These are high quality with 7 elements. They will also retain some auto functions. The bad news is nearly every Maxxum or Sony Camera has a different way to set the camera for using these lenses. Minolta was supposedly working on one of those adapters which would even turn those old Minolta MD or MC lenses to AF with the 2X adapter.
If the sekors are pentax screw mount(m42’s) the sony’s will with a threaded to alpha adaptor. There is no need for corrective glass since the registration distance is the same but you will have to adjust focus and apertures manually. The SONY slt’s have phase focus peaking so as you adjust manually, the outlines that come into focus will show a collored out line indicating phase focusing. Some adaptors come with a focus confirm chip and you can get confirm chips that will approximate electrically the mm size of your lens so that as you stop down manually then adjust focus, the adaptor indicates proper focus without the need for focus peaking.