This question is written as a simple "yes or no" question without any additional details. The answer to the question you are asking here is "Yes".
But reviewing context and reading in-between the lines, I can see that you have asked three other similar questions in the past few days and have gotten a lot of good advice. Based in this context, it is apparent that you are struggling with upgrading, but in four questions, you have yet to share with us any enlightening technical details that might illuminate why your system can't upgrade.
If you insist on upgrading this installation, we can help with this. However you should know that in order for us to help, we will have to understand the exact problem that is preventing you from upgrading. This requires not only collaboration, but a significant amount of technical prowess on your end. Asking "can it be done" with no additional info, as you've done here, will not get you any further to your goal.
Because everyone uses their system differently and anyone can make careless mistakes, the possible reasons why you can't upgrade are practically infinite. Simply telling us that something doesn't work isn't enough for us to understand the technical details of a particular problem. We need to know why it's not working and if neither of us can figure out the why, then it will be difficult to figure out a solution. Since we don't have physical access to your device and since we don't know the full history of your installation, we are predominantly at your mercy in terms of figuring out the "why".
Based on the lack of details in your previous questions that might indicate a solvable problem, it seems clear to me that it would be a lot easier for you to reinstall 18.04 cleanly, than it would be for you to identify the problem (or problems) that need to be fixed in order for you to proceed.
Thankfully, setting up and migrating to a clean installation is bound to work. It takes a predictable, fixed amount of time, and won't contain any of the possible baggage that your current installation is saddled with.
In the time it's taken you so far, you could have cleanly installed 18.04 a dozen or more times. I encourage you at this point to take a cost-benefit analysis and ask yourself if it is worth all this time to keep trying to upgrade without any tangible results, or if your time and effort would be better spent just doing a clean installation and being done with it.
Remember that in order to reduce the potential for problems with future upgrades, don't wait until after your release goes EOL. Once you are on 18.04, make a note to remind yourself to be sure to upgrade before April 2023.
