We have to receive Holy Communion (physically) because Jesus commanded us to receive. “Unless you eat my flesh and drink my blood, you have no life in you” (John 6:53). And at the Last Supper, he said “Take and eat, for this is my Body… take and drink, this cup is my blood”, and added, “Do this to remember me.” Clearly, we must partake of His Body and Blood in the Holy Communion as often as possible.
Spiritual communion, on the other hand, is not Holy Communion at all. Spiritual communion is recommended when it is not possible to receive Holy Communion, so that some graces may be given to sustain us in its absence. There is true graces in spiritual communion, mind you, and great ones too, but not the same as receiving Holy Communion actually, for which it can never replace.
It is for this reason that when the Pope gave the dispensation for receiving spiritual communion this year due to covid-19 lockdown, it is given with the condition that it is for those who have no access to Holy Mass, or are not able to go due to health risks. This means that this dispensation ceases to be applicable to you the moment mass is available to you again and you are not under health risk to go, even when the dispensation would still be offered in general for those who cannot go due to their particular health condition, or cannot participate due to capacity restriction.
In other words, while currently dispensation from Sunday obligation is still being offered, whenever Mass is available and if I am not in high risk to go, I must make an effort to go as often and as regularly as church capacity allows. And only when I have made an effort and am not able to obtain a seat may I be dispensed from my Sunday obligation to attend Mass and receive Holy Communion. Then spiritual communion is my recourse until the next available opportunity to attend Mass.