addy.io has been working great for me for a few years. I've not had them rejected on any site yet. I have the cheapest plan which has been enough for me so far.

Hi, u should use SimpleLogin or Addy as email masked, those services are Open Source and u use free plan

Rejecting temporary email (particularly mailinator but sometimes even hotmail) has been a common thing. Fastmail temporary addresses usually work, but you need a paid fastmail account to get them.

I haven’t had issues anywhere with the @duck.com (duckduckgo) masking service.

SimpleLogin has been working for me

Thinking about switching to Addy.io tho

Edit: except for github. I haven't found anything that worked to sign up for github.

I've had a very positive experience with SimpleLogin via ProtonPass. I've only had maybe 2-3 out of 100 sites that rejected a "@passmail.net" address, but took a "proton.me".

I couldn't make accounts on Bluesky and Github with SimpleLogin. Ended up using my Tuta address for bsky. Didn't try another option for Github.

Addy.io is my go to