I would buy the Titan long before I buy the ram. It will outlast them

The initial word on the Titan was that it was pretty good.  But it never sold well and I think it may have been discontinued, which means dealer support (already a sore spot for Nissan) could be a bit spotty.  There also have been some rumors about some problems, now that it's been out a while.

With Ram, you know what you're getting.  The engines (especially the 5.7) and transmissions are generally good; the electrical and other surrounding parts are not.  Overall, quality seems to have actually come up a bit since Stellantis entered the picture (surprising, I know!) and the new ones are not horrible.  Considering the discounts available these days, you could get one and set aside a slush fund to cover any major repairs that might be needed down the road (or if you are looking at a few-year-old ones, see how much they will haggle with you).

IMO, the trend overall in the full size truck segment is that the quality of all the brands is regressing to the mean: Toyota and Ford are falling off, GM is mediocre but steady, and Ram is improving somewhat.  Nissan is probably in the same middle; not horrible, not great.

Speaking of dealers, that might actually be the deciding factor.  I'd go with whichever has the more reputable local dealer.