Personally the issue with immortality is not boredom. But whether you age and whether you can stay healthy. Most people at the end of their life accept dying off, just because it is unbearable to physically live in any way an active life. Not because they want to. I personally know I do not want to go, but I sure the heck would not want to stick around feeling constantly in pain and increasingly experiencing a decline in mental facilities.
Simple things like: When you go through a work day when you in your 20-30s and when you go through your work day when you are 50+, is a major difference in how tired and sore you feel at the end of the day. Old age is what forces people to retire, not because they want to or can afford to but because they are physically or mentally not well off and have to. Getting old puts a timer on what you can do and how long you can do it.
If I was immortal, and could stay healthy, I would go for it, even though I know I would end up outliving and burying my wife and kids. Humans can always find new things to do, or even go back to old things done before.
As far as watching people you love die. Yes, you are going to grieve, but if you were constantly young and healthy you might move on better if you can continue to build new relationships in your life. It is harder when you are old to do so, without constantly having people leave you because you are all old and dying off. Under normal circumstances 20 somethings do not want to hang with 30+, 30+ do not want to hang with 50+, and 50+ are annoyed that they have less and less people to choose from for friends. Yes, there are always exceptions, but that is a consistent rule.
I am at the age where I have lost pretty much everyone that were my elders growing up, my peers have been dying off for health/age reasons, instead of the reason being it was bad luck or their/someone's stupidity.
So immortality is great as long as you are not aging.
The Myth of Tithones from the Greek actually puts it into a good perspective:
https://en.wikipedia.org/wiki/Tithonus
"but when loathsome old age pressed full upon him, and he could not move nor lift his limbs, this seemed to her in her heart the best counsel: she laid him in a room and put to the shining doors. There he babbles endlessly, and no more has strength at all, such as once he had in his supple limbs"
Now what are you going to do about your immortality when the government finds out is another can of worms. Genetic tracing has gotten good enough they are catching rapists and others crimes that had become cold and decades old just with online genealogy sites
.https://www.nytimes.com/2018/04/26/us/golden-state-killer.html#:~:text=Joseph%20James%20DeAngelo%2C%2072%2C%20was%20arrested%20at%20a%20home%20in,in%20the%201970s%20and%20'80s.