Sorry then, didn’t mean to give you unhelpful advice. Been there, when I was on ADHD meds I couldn’t eat much throughout the day.

120g sounds really high to me. What source is telling you that? When I was tracking my macros I think I settled on a target of somewhere around 60 g / day and found it frankly impossible to hit sustainably.

To go back to your original question, IIRC the formula I thought was backed the most up by some studies (but sorry, I didn’t save the source,and it was still a matter of active study and debate at the time) was about 0.75 x 0.001 x (body mass in kilograms). So, an 80Kg person would want 0.75 x 80g = 60g. This is markedly lower than the average bro science adages of 1g protein per kg of body mass.

120g is body builder level, it’s well into the diminishing returns range and I think anything above like 90 is people trying to game the curve and find a “reasonable” level before it’s really not worth it.

If you’re not in a hurry, just eat “more protein” and don’t think too much about it. I’m not vegan so maybe my experience isn’t welcome here, but I spent a while obsessed with protein “options” when really a solid third of my intake ends up coming from ordinary staples like bread and pasta. I track what I eat and a day of regular food for me gives me 50-60 grams piecemeal on days I don’t eat meat, which is most days. I think a shake on top of that takes you to “high protein” without hitting unnecessary body builder levels. I’m not familiar with the vegan shakes at all so I don’t know. It does seem much harder for full time vegan people, I’m aware this is just pontificating.

Granted, we eat a lot of legumes and only get brown rice etc. I recommend you figure out a lentil seasoning that you can get obsessed with. I found that a chickpea pasta sauce tradition exists and it’s cheap vegan protein that doesn’t really change my day to day life. I could probably dump some TVP in there too. Legumes are your friend, just cook them long enough to make sure they don’t give you gas.

You don’t need to optimize every last thing, the internet turns up the noise all the way especially on things like nutrition. If you need more protein, just make some effort to get more in than before, you should be fine. It’s extra bad now that companies have decided that customers are obsessed with protein and the word protein is something you get slapped by in the face a dozen times every day now. If you really care about a number, there are a few different guidelines and the lowest certainly won’t be too low. I’m not a doctor but 60 as an obligatory minimum + trying to get to 90 most days should be enough if you’re taking it easy.