Dangerous? Definitely not. Well planned out? Also, definitely not.
You’ve been on test so long, there’s no reason to do a 2 week PCT, which wouldn’t even be beneficial had you not been on TRT.
What you’re basically asking is, “Is this a good method of blast & cruising? (B&C)” And the answer to that is quite simply, no. Look more into B&C and see what others do.
I personally run test E for about 10 weeks at 500mg (alongside low dose Primo) with an oral for the first 4-6 of those and quite simply go back to 250mg for another 10-15 weeks with the later of 15 weeks if my bloods aren’t in check (cholesterol, RBC, livers, etc.).
As far as IM vs subQ goes, I don’t know; I’ve never tried SQ. However, I heard SQ is better for TRT as it’ll give you a steady T flow to reduce mood swings. Though from what I’ve found, keeping your hormone levels in check with AIs will do the same.