I believe they are seeing higher prices for those domains so they are passing it along. Email I received from Namecheap.com:
We partner with many registries to bring you a wide range of top-level domains, but occasionally their prices increase, which means we need to increase our prices too.
On September 1, 2023, the domains registry for .COM and .XYZ will implement universal price increases of up to 9% for .COM renewals, and up to 9% for .XYZ renewals, registrations, and transfers.
If you want to take advantage of the current price tag, renew your .COM and renew, register, or transfer your .XYZ domains before September 1, 2023.
It always puzzles me when technology gets more expensive. Processors and storage are cheaper, why does it cost more for them to have a database entry for a domain that’s updated every X years?