Does Android auto-switch between SIMs for data on dual-SIM phones when one of the SIMs has poor reception?

If you're using the internet on the phone, does Android auto-switch between SIMs on dual-SIM phones when one of the SIMs has poor reception? https://honestmobile.co.uk/ seem to think some phones do and they advise turning it off so as not to interfere with their own app that selects from the providers they MVNO on top of. It would be a handy alternative to Speedify VPN to bond separate mobiles, if the SIMs in those could be put in a dual SIM phone. (By the way, I don't have an financial interest or otherwise in Honest Mobile, nor Speedify). Thank you.