I would say (as someone who retrained in her 40s and got a new career) that the only way to not be seen as a childminder is to retrain so that you have a shiny new qualification. I too was completely unemployable after 17 years as a SAHM, except that during that time I did a degree and so I had a recent qualification. If I hadn't done that, I'd still be unemployed.
I know that your situation is slightly different, because you've been working all this time, but being a childminder for 30 years only really qualifies you to keep doing that. You could probably get work as a cleaner, as a care assistant, maybe in a supermarket stacking shelves, delivering food or packages, but it's all minimum wage jobs and most of it is quite physical - would you be up for that?
Most admin jobs these days will require a good level of competence in Microsoft Office programmes (Outlook, Word, Excel, Powerpoint, OneNote), able to use Teams, and above all you need recent experience - no one is going to look at 30-year-old admin experience and hire you based on that, because everything has changed in that time. Most offices are paper-free these days, no one has a phone on their desk any more, everything is digital.