DW - Ftp issue? host issue?

I have an old version of DW - C5.5.

Trying to update an established website today, I got a problem with the Ftp connection (can't connect to host).

(I haven't posted to this site since July 19, so don't know when the problem would have first occured)

My hosting provider (a local organisation, using Linux), tells me it's not the port etc, and that they haven't changed the settings.  They point out the age of my software, and also mention TSL 1.2 and DW's not working with it.

Looking at previous posts on here, this might indicate problems with DW OR (just?) older versions of DW and ftp clients?

I don't know enough about hosting to be sure where the problem is and thus how to rectify.

Is it my version of DW?

Is it DW?

If I move it from the current host, keeping my current DW, that should resolve it (I uploaded last week to another site that is hosted by IONOS) (at least for now).

I can't afford to upversion my DW, so would have to change the website in question to a wordpress/free one.

And where posters mention Filezilla - are Filezilla the host?  So would I move my domain to them?  Do they work with old DW?