No. Valve was never against legit developers using their infrastructure for games sold elsewhere even if Valve dont get any cut. If you have game that sold 1000 copies on Steam you can still generate 10,000 keys for selling elsewhere.
What they clamped down on was developers who built $0.01 game for trading cards farming. Now Valve just have some fair usage rules so developer of game that sold 10 copies on Steam can't request 1,000,000 keys for it.
Disclosure: I am indie game studio co-fouder so Steam keys is something we deal with.
I found it - in February 2023 it looks like added some limits and are enforcing that Steam customers don't get a worse deal than customers who use CD keys.
But yes they have clamped down on the fake games for trading card farming too.
It was a news in February 2023, but Steam had this as part of their ToS for decade or more. Basically Valve want you to run the same discounts on Steam as you run on other stores.
AFAIK it's perfectly fine to temporary run something like lowest-ever price outside of Steam on a condition that within some timeframe (not sure about timing) there will be similar sale on Steam.
What they clamped down on was developers who built $0.01 game for trading cards farming. Now Valve just have some fair usage rules so developer of game that sold 10 copies on Steam can't request 1,000,000 keys for it.
Disclosure: I am indie game studio co-fouder so Steam keys is something we deal with.