The only thing weird here is that if you use the same tool to see fees on which network is higher, you get a different results.
Blockcypher reports higher fee on mainnet compared to testnet 0.00069 BTC/KB vs 0.00032 BTC/KB
mempool.space reports higher fee on testnet compared to mainnet 25 sat/vB vs 47 sat/vB

Sometimes these fee estimators either have bugs or use different methodology that returns different fee estimation. I believe mempool.space is more accurate though.