Well if there was a modern alternative I would have thought this would have come up before I've tried a fair few amps in my time but not everything out there I have had various Sansui's over the years and done some comparisons along the way what I found I kept going back to Sansui every time and that Is what I use every day as per my signature however I did find the Saksa 80 ($2000) from Hugh Dean Aspen Amplifiers was pretty close in sound signature to the Sansui's to the point that it survived in my collection the longest because I couldn't bring myself to sell it because it did sound so good but in the end I was doing a bit of a downsize system wise and I sold it I still have various Sansui's though.
If you're trying to find something that sounds the same but costs a lot less well good luck Sansui were at the top of the game all those years ago some other brands up there would include Luxman Accuphase and there would be others but their prices are up there as well, the two you've mentioned PM5005 (which I have had) and Rotel A10 aren't in the same class don't bother they probably won't satisfy.
There's a reason these amps from Japan command the high prices they were built to a high standard when there was pride in putting out a quality product for the right reasons not just to make a buck, that legacy remains to this day and beyond they just sound right to the person who likes a balance of sweet tone, musicality and accuracy.
You could probably pick up one of the lower spec Sansui like the one you had for your budget put a WTB in the classifieds never know what might turn up plenty of hoarders on here eventually they let some things go 😉
@Cafad is the Sansui comparison guru he might be able to suggest something here.