I had a similar problem with changing especially to the D chord. In addition to the advice that Rob @RobDickinson and James @Socio gave I highly recommend including Richard’s finger independence related advice into your practice routine:
This is similar to what Joshua @Jamolay and Hilary @southpaw6 recommended above.
I did this for a month and now all of a sudden I’m now able to change to the D chord with all fingers at once. I can HIGHLY recommend this practice.
In case it helps, I’ve started 11 months ago, and I’ve just completed Module 9 and same as Nicole @NicoleKKB from my perspective I don’t have the impression that you should be already far ahead with your techniques. Air changes are not super basic stuff, for me personally it’s quite the opposite. Experiencing frustration is normal, once in a while going back to what we have learned before and doing consolidation will help and is part of the process. With that, I’m absolutely convinced that you WILL get decent at guitar.
Good luck Medu!