Hey there,

You can add nodes to help sync the wallet. You will be able to find some here on Beam website:
https://beam.mw/downloads/

You can also find more nodes on both https://beamprivacy.community/ (node tab on the right)
And https://www.raskul.com/beam-nodes/

If you cannot add them directly in the wallet, you can add to the settings file (settings.ini), you can find the file locations here:
https://documentation.beam.mw/en/latest/rtd_pages/user_files_and_locations.html