[Question] PWM to ChargeTech PLUG

Currently have:

• 2x 12v 100W panels.
• 1x 54AH ChargeTech PLUG

Waiting to arrive:

• Solar BMS (Ordered; expected in July/August)
• 100Ah LiFeMnPO4 battery (One to start, planning on expanding to 200 or 400Ah eventually)

Question: In the interim couple months, waiting for the Solar BMS & larger battery to arrive, would it be okay to get a cheap 20A PWM charge controller and connect it directly to the 12v input on the ChargeTech PLUG battery system?

Edit: Correction - Looking to supply 1.8A @ 24v from the output of a 24v PWM charge controller connected to two 12v 100W panels in series.