28M; HELP! Zone based running

My (28M) last 3 running data. RHR: 52. I have been posting here to get feedback on Zone based running. I was told that Zone 2 is what I should target to improve my cardiovascular health (not targeting weight loss, infact I’m skinny). Today I had to literally force myself to remain in Zone 2, was almost kinda fast paced walking instead of running. Had to keep stopping and switching in between slow running and walking. I really want to run but it seems I am unable to stay in Zone 2. I can run in Zone 4 and Zone 5 for elongated periods of time (as in the Day1 and Day2 snaps) without feeling any dizziness or major discomfort (except rapid heavy breathing). Have recently started to run. Also, VO2max was 30.2 when I started running a couple of weeks back (3times a week) but ever since I started it has been increasing steadily (now 32.8). Not sure what to make out of all this. I probably feel my Zones are not correct. Help!