Is it safe to use Eustachi for popping of ears?

Hello doctor,

Three months before, I got an ear infection in my right ear and I had a ringing sound in my right ear. I went to a doctor and was given ear drops and medicines, the ear infection went away but the right ear still felt blocked. I was told to take a tympanogram and they said that I had fluid behind my ear, I was given a medicine for it. After a few days, my left ear started getting blocked too and it started ringing too. My nose also started getting blocked every morning and I had a popping sound in both my ears when I swallow and sometimes it randomly pops. I was told to use Otrivin and have Alaspan AM tablet for five days. The next week the issue was still there and I also started having a cough, I was told to have Alex SF cough syrup for a week, Avamys nasal spray for two weeks two puffs in each nostril morning and night and Relent tablet. After two weeks the cough went away but I still had the issue with my ears but my ears started feeling less blocked, I did another tympanogram and they said I still had fluid behind my eardrums, I was told to continue the Avamys nasal spray and the Relent tablet and was also given Predmet 8 mg tablet for five days. A month passed and my ears still had the popping sound when I swallow and randomly. I went to the doctor again and took another tympanogram and he said the fluid is almost completely gone and I should continue the Avamys nasal spray and Relent tablet. I also had a pure tone audiometry test which he said was normal. I have been using the Avamys nasal spray and Relent tablet for the past two months throughout and I was told I did not have to take the Relent tablets anymore and the fluid was completely gone. I still had popping/clicking sounds when I swallow and my ears still feel a bit blocked so I was told to keep using the Avamys nasal spray. At the end of last month I could not get the Avamys nasal spray so I was told to use Fluticone-FT instead. I have been using it ever since. And I was also told to do the Valsalva maneuver 10 times every morning and night which I have been doing. My right ear pop with no issues but my left ear usually does not pop and it has only popped three times last month. I found something online called the eustachi that says it helps with popping ears, is it safe to use? I still have popping/crackling in my ear when I swallow. I feel like the ringing sound has reduced but I am not sure. I have not been able to go to the hospital because of the Coronavirus warnings and would like to ask what exactly is wrong with me and how long will it take to heal. It is already been three months, should I keep using the nasal spray?