Hello,
Yes, using this command has an advantage of using the B20 that was suggested by the ISP, but also aggregating all the other bands as secondary bands. In theory this should leave you with the latency of the carrier suggested settings, but similar throughput as in Auto mode.
Another user has written a script to constantly check the cell lock status that is available here: RUTX50 - Locking 5G-NSA CA bands manually - #9 by bifteki. The values will need to be adjusted according to the particular band you are connected to.
Please report if switching the primary band helped!
Best regards,