This isn't actually Gandi fault.
The amount of spam come from .xyz .top .cam etc are too hight and sysadmin usually factor domain tld into spam scoring.
so using a .com may increase your chance hitting inbox actually.
I've run into this same issue communicating with potential employers via GANDI mail--more often then not when I make a followup call my email is in their SPAM folder.
My sister-in-law's employer's mail service (k-12 school district) ALWAYS bounces back email from myself and my wife, and their sysadmin always says "Nope. Not a problem on my end."
When I was finding a new job last year, every time sent recruiters an email with my resume (attached as a pdf), I had to ring them afterwards to check if they had actually received it.
I ended up switching to Google Workspace, just so that my emails actually had a chance of not landing in the recipients spam folder.