Membership users - mass level change

I need some advice with Membership plugin - I can’t find option for bulk user change.
My WP install have 800+ users with custom role assigned, not “subscriber”, let say “paying”. I need to have them in Membership. I would like to mass apply them certain level in plugin.

As I seen in the admin page Membership > All members, I can assign them Membership level one by one. There is no way to sort or filter them to see only users with custom role. Moreover, pagination at the bottom of this list, is not clickable

On users panel in WP admin there is “Permissions” setting, to allow bulk change. I think, in this place should be also possibility to assing Membership levels.

Can someone tell me the workaround, how to cope with mass user attributes change in Members? Thanks in advance!