I just realized my tax filer does not encrypt my password. Can I anything do for the financial data (eg SSN) that I gave?

Last year due to a complicated tax scenario (for my skills), I used an online tax website recommended by a friend to do my taxes. They were efficient in their job and I wanted to use their services again this year to save time. I had forgotten my password so tried to reset it. Turns out, they stored my password in plain text. Apparently that was to enable their staff to update any information that I provided in case it was incorrect.

I am worried about the financial data that I have already provided to them. I think as a user I have to consider it compromised. But I am a bit optimist so wondering if I can do anything to protect my data.

They don’t seem to be GDPR compliant so I don’t think they will simply delete my data but I definitely am going to request for it.