The ideas on probiotics seem to be shifting. They should be used more like a medicine for specific conditions not as a daily supplement. The idea is that bacteria in probiotics don’t permanently colonize the gut, they temporarily displace your own good and bad bacteria.
The better strategy is to encourage your own beneficial bacteria - fermented foods as you mentioned are great. Eating a wide variety of vegetables and fiber is great. If you want to supplement I’d look at a prebiotic. A prebiotic is just fiber that feeds your benefical gut bacteria.