I agree that it's a fair question to ask because it's hard to show anything definitive statistically, but that 2018 team was full of vets. I think the shoddy defense in the 2024 wild card round can be at least partially attributed to playoff inexperience. The 2025 Brewers are one of the youngest teams in MLB.
I've just seen it too many times where some of these experienced teams coast through the regular season and then suddenly find another gear in the postseason. I think of the Castellanos quote in particular: “A lot of time I have trouble keeping focused everyday 9 innings in the regular season, but with the postseason the baseball’s incredible you don’t have a choice but to be locked in and I think that’s just kinda why I’m playing better.”