Is it permissible to commit minor sins, not major ones, alongside good deeds, or is it also obligatory to abandon all disobedience, in pursuit of entering the highest Paradise (Jannat al-Firdaws)? And is that sufficient, given feelings of suppression and a lack of happiness?

It is not permissible to intentionally commit a sin, even if it is a minor one, because leniency regarding it poses a great danger. Minor sins lead to major sins, and their accumulation can destroy a person. A person may consider a sin minor, while it is great in the sight of Allah. A believer must avoid all sins, and if a sin is committed, they must offer sincere repentance. Persistence in committing a minor sin makes it a major one. As for one who avoids major sins and does not persist in minor ones, it is hoped that their minor misdeeds will be expiated. Regarding the restrictions and similar matters you mentioned, there is no recourse except patience in obeying Allah and refraining from disobeying Him, along while constantly supplicating and seeking Allah's help.