Yes Nextcloud Maps does provide geovavorites and I’ve been using it for years. And there’s also an Android client which is quite basic but does the job 👍

https://f-droid.org/packages/it.danieleverducci.nextcloudmaps

Thanks for reminding about this project! Had a look a year back and it looked quite green at the time. Any first hand experience, how did you install it?

You have listed some good options there👍 One additional possibility: what about repurposing an old enterprise workstation, like Dell Optiplex, HP Elitedesk, Lenovo Thinkcentre etc.? They can be bought for around 50-100 e/$. For a similar use case I’ve been running an Optiplex 7010 SFF (Small form factor) with i5 3XXX and 16G of ddr3 and it has been plenty of powerfull for the purpose.