[Ask CashDoc] Vascular health?

These photos were taken after blood collection and MRI scans yesterday.

I am currently a liver transplant candidate. There is no suitable liver for me, so I am waiting without a specific timeline. I have undergone a total of nine transarterial chemoembolizations to remove the tumor and maintain my health, but the tumor keeps recurring after removal, and it keeps happening repeatedly. Therefore, I have blood tests and MRI scans about once a month. Each time, I need to locate a blood vessel, draw blood, and perform the tests. I have never had blood drawn from my arm because there are no accessible veins.ㅠㅠ So, I have to have needles inserted into the back of my hand, wrist, or top of my foot.

When I get an MRI scan, I have to insert a very thick needle, and I'm so scared. Among the nurses, I'm also known for having no veins, and everyone avoids me.ㅠㅠ I sometimes fail to draw blood on the first try and have to poke two or three times.

When I see healthy people, they seem to have many and thick blood vessels. Is there a way to develop more blood vessels or increase blood flow? Are there foods or exercises that are good for vascular health? I really want to know about these things.