I think there are different levels of ‘heter’. Sometimes the heter given is “usually not allowed, but this case is different”- probably perfectly fine to rely on such a heter, maybe even a good idea; then there’s “technically you can/there is what to rely on- but better not to”- in which case, you should think long and hard before going ahead. Heterim are important, and following a heter does not mean one is weak, lazy, or looking for convenience; more important is that you read between the lines of the heter (like the above examples) and that you don’t shop for heterim- as in, you will follow the heter you got, but you will also follow the issurim of this Rav.
I also have a nisayon story: I am married to a sefardi and our Rav holds that sheitals are assur (this is a hard psak for me to follow as I grew up ashkenazi). Anyway, when I was interviewing for a professional job, I was considering asking for a heter to wear a sheital to interviews and to work, should I land a job. I figured it would be an easy heter to get, since so many poskim hold that sheitals are fine and even preferable. My Rav did say I can rely on those psakim, but left me with the following thought: “If Hashem wants you to land a job, you will land it no matter what you wear on your head; if He does not want you to get a job, you won’t get it even with the fanciest, most natural wig.” I decided to interview in a tichel, and I got the job! All my worrying about a tichel setting me back turned out to be unfounded and I’m really glad I understood what my Rav really thought.