It really depends on whether Douglas can avoid Sanders' straighter faster punches early on. I don't think he has the chin to take flush shots from Sanders and come out of it vertically. Douglas' improved determination and heart only comes into it in the second half of the fight. I think Sanders will take it but you could make an argument for either to be honest.
Did Sanders have decent stamina at this stage? No. Unless he ko's Douglas in the first 4 rounds, Douglas will take over and win by a late stoppage. Douglas tko 8.
Duglas drowns him late, but there is the question of how well Buster can adjust to a rangy, extremely accurate southpaw. Probably does well enough.
The difference between Tokyo Douglas and Hanover Sanders is Buster produced a tactile masterclass over Mike Tyson. Saxony Sanders didn't produce a performance for the ages. He just turned up while in semi retirement , hit Wlad on the chin and that was that. Pretty much the same Sanders was blown apart an shown to be totally inept vs Vitali. Tokyo Dougie was better than semi retired Sanders
That version of Buster Douglas beats the hell out of Sanders and stop him with in 8rds. That version of Douglas beat any heavyweight of the last 10-15 yrs.
Tokyo Douglas was laser focused (regardless the Kdown), thus he is not going to be caught flush by Sanders. Barring a lucky shot, Sanders simply has nothing in his arsenal to prevail. Douglas wins; probably by like stoppage.