Attached is an idea that might work nicely for a drive control that can be varied in software by the NANO on a band by band basis.
The original drive control, RV1, is removed and a few parts added, along with a digital pot (I2C control) in place of R3 below to form an attenuator in the RF path.
With some careful work it should be possible to design a small PCB that fits into the holes vacated by RV1, either vertically or horizontally.
(the schematic is from page 62 of the book by Randy L. Henerson on designing a Transveiver. Its avery old book (1997) ISBN 0-07-028263-3)