Messy dual boot partitions / Please help to clean them up

Please excuse my mistakes both in English and in Ubuntu terminology.

I recently did a reinstallation of my computer. I'm running now Ubuntu 20.04.3 LTS on a computer with a 1TB Hard disk and 512GB SSD disk. I have no access to a USB live boot nor to a CD, so I did the formatting through Unetbootin or a similar program (can't remember now).

At the moment of creating the partitions, there was an automatic division and I accepted it, also making some changes I found on a guide. I knew I was not doing it right, but I thought I could change it later once I could dive online.

Now it's obvious that I'm lacking space on my root partition and probably need to delete some non-sense partitions on my SSD. The issue is that I still cannot boot from a USB or CD.

Here are my questions:

1. Can somebody advise on the best way to clean up and use my partitions? I'm looking to maintain an Ubuntu/Windows dual boot, but I use Windows very occasionally only for one software. Should I create any partition on the Hard disk as well? Seems like it's not getting any use now?
2. Is there a way to do this running from the actual boot, for example using "growpart"?

Thank you

UPDATE

From the information you have provided it’s not clear which, if any, partitions can be deleted but since they are small they are not worth messing with. Your root partition is left of a NTFS partition. In this situation manipulation of that partition in Linux can break the Windows boot process. If I were you I would:

1. Backup your data on partition 6 and 7
2. Unmount partition 6
3. Using GParted shrink partition 6 and move it as far as possible to the right. The amount you shrink by will end up in your root partition after the following steps.
4. Using Windows disk management move partition 5 as far as possible to the right, next to partition 6
5. Resize partition 7. Normally you would boot into a live session to do this. You may be able to do this with the Ubuntu installation media you used recently. If not one of the following processes will enable you to do this but they are not beginner level.

How to modify partitions without a live USB/CD

How can I resize an ext root partition at runtime?

Good luck, let us know how you get on.