The one-day international series was drawn 1-1 after less than 28 overs of play were possible in Leeds, with one rain delay and resumption before the game was called in the first innings with South Africa on 159 for two.
In Buttler's first month since taking over from World Cup-winning captain Eoin Morgan, he has had to contend with a hectic schedule of cricket as well as dealing with a hole in the team following the ODI retirement of Ben Stokes.
England are currently nine games into a hectic period which will see them take to the field 12 times in 24 days and they have had just one dedicated training day so far during that time, something the new captain revealed has been challenging.
"It's tough," Buttler said after the washed-out ODI in West Yorkshire. "A lot of the time around training is when you do your best work, away from the pressures of the game, having good conversations and having a feel for where the group is at.
"And not just always in game mode, preparing for guys on the day. To get the highest standard of cricket possible, you need to prepare properly. Hopefully that's something we can look at going forward.
"As a new captain, just having that time to bed in and do that work around your players and with your coaches.
"That's been a frustration to be truthfully honest - it would be nice to have that time to do the work.
"But we don't, so you just have to adapt and find the best way. It's been a good challenge."
Buttler's England went into the final game looking to avoid the prospect of a third straight white-ball series defeat, but they will have to settle for a draw.
However, the 31-year-old believes his side are trying to play the right way despite struggling in matches against India and South Africa.
"It confirms that the way we want to play is the right way and we haven't quite achieved that. I think especially with the bat," Buttler said.
"It's a strength of ours for a long time and we haven't quite lived up to the standards that we know we can."
In the overs possible, Quinton De Kock was denied an 18th ODI century as he struck a cleverly crafted 92 from 76 to help set a solid platform for the Proteas.
South Africa had their last series against India in June and De Kock said it was good to spend time on the field.
"I think obviously it's nice going out there and scoring runs for the guys," the South Africa wicketkeeper said.
"Obviously we've had a little bit of time off from our last series, so it's just nice to get out there and spend some time in the middle.
"It's always satisfying going with a high strike rate or a low strike rate, as long as I can help the team it's always satisfying I guess."