I have an XL Vitus e-Escarpe with a 488mm reach, a little short relative to some XL bikes which are reaching 510mm or more, but long compared to anything from a few years ago. My normal bike is a Scott Genius with 505mm reach and 5mm longer stem, so its 20mm longer in total. Doesnt sound much but 20mm is the difference between sizes for most brands. If you dont know what sort of Reach you want find out what reach your old bikes were for comparison.
Also worth noting that at 6ft4 there is much more potential for difference in leg to body length. Many 6ft4 riders can fit very long seat posts, me i must have short legs as i cant get away with more than 150mm dropper on a 520mm frame. So also knowing your max seat height will let you work out what bikes will suit.