Let me separate the two questions here: too busy to attend mass on Sunday and online mass.
I’ll answer the second part first. Online mass is not mass. It never was. During the covid lockdown, when the Pope allowed online mass, that was never to replace in person mass, nor to declare that online mass is mass. It was simply to dispense the faithful from Sunday obligation to go to mass, with the added aid that we are not completely deprived of the benefit of the liturgy. All that time we did not go to mass at all. We were sustained outside of mass through spiritual communion and viewing the liturgy remotely.
The dispensation is therefore only valid when it is physically or morally impossible for us to go to mass, i.e., the Church is locked down, or I’m sick or high risk, or someone I must look after is sick or high risk.
And so with the first question, one must evaluate to the reason behind not being able to go to Mass on Sunday. We’ve already established that online mass is not mass, so unless you are either physically or morally not able to go to mass, online mass would not help you fulfill the Sunday obligation.
You mentioned the reason being your heavy work schedule. Does it mean that you are working on Sundays, or that your work during the week is so heavy that you need Sunday to take care of other priorities? If you are working on Sunday, is it necessary? If not, maybe there is where you should start by stop working on Sundays. But if you have to work on Sunday because you are a nurse or on shift or likewise, or if you are financially under duress, then it is best to talk to your pastor. I know some in this situation make Monday or another day their day dedicated to the Lord.
And if it is not working on Sunday, but that the rest of the week is too busy, you just need Sunday to be with your husband first or likewise, then I suggest you also talk to your pastor. Obviously there is a pastoral reality here that require fuller understanding to decide what is the right thing to do.
The bottomline is, giving the Lord’s Day (Sunday) back to the Lord is of the highest priority, for no one is more important in our life than God, and without seriously making an effort to worship God first, apart from Him, we really can do nothing, in our own walk of faith, our marriage and our family, and everything else that we do. However, God is not without compassion. Sometimes we are stuck in a very bad situation or sometimes we ourselves are stuck with the wrong ideas. And so I encourage you to bring your situation to your parish priest and ask for wisdom, and meanwhile ask God to show you how to make it work.