Well I’ve made a start.
I opened the laptop and wiped/blow out the fan. There really wasn’t much dust. But it gave me confidence to see about replacing it myself. Do you know of a good place to buy a replacement fan? Do I find a reputable seller on eBay and get it there or does anyone know of other sources for computer parts.
Also I ran the Dell SupportAssist, Hardware scan. The battery said “warning”; but everything else, including the fan, said “pass”. (That makes since with the battery because it drains quickly when not plugged in).
Then I’ve updated to Windows 11. It took several hours to do, but it didn’t cost.
Unfortunately the fan is still quite loud, so I going to try replacing it.