Having just assembled a Drop CTRL based build, and having removed several batteries from other boards, I wouldn’t worry too much about the extra weight. The CTRL is not a copper-weighted monster, but it’s a substantial board and the LiPo pouches that go into these keyboards are not very heavy by comparison.
That said, the plastic-cased budget custom category is in a very healthy place right now, with much more thought put into the designs than into the gamer boards of years’ past.