In jerboa go to sidebar (swipe left to right on main feed, or elliptical in upper left corner), Settings, YourSettings, there should be a default option to change your preferred main feed. I found I had to hit save settings at the bottom several times for it to stick
The web-ui has a setting for this and it works. Jerboa has these options in setting, but as of v0.34 they seem to be ignored... at least for some people.
Try setting these options in the web-ui
Try updating Jerboa to the latest release available to you
If Jerboa doesn't respect those settings, set them in the top-bar. Jerboa often remembers that even if you swipe away from that app (though it does forget occasionally)
This is a relatively frequently reported issue, I have to think that it will get addressed eventually, but the devs are maxed out fixing performance problems and existential abuse issues. Quality of life features like this will take a back seat unless a community member steps up in github with a PR and some tests.
If you have the playstore version of the app, I don't think so. If you're on Android and use the GitHub or the FDroid version, yes. I'm not sure when playstore will get the newest update.