Watch the videos yourself, one of them was shooting for a couple of hours and already used 2/3 of the battery.
Thats the best thing about youtube videos that are not sponsored, u get to see what the experience is like before you make a decision to buy it or not.
Again maye for u, you dont shoot no more than 3 hours and only take a few shots here and there but maybe for others it will be a issue.
Again, these videos will help make you make a decision based on your needs.
O and dont worry, the A7s3 will have flaws too so dont think that people here are bashing R5 and the A7s3 is perfect and will blow it out of the way, it wont. they both have flaws. deal with it or look for another camera that has the least amount of flaws.
Why did you get rid of the a7mk3 if by your thoughts, it was more or less a flawless camera for your needs?
What was it missing that made you switch?