Junior

Don't do it! Decades later, after Sr has passed, still legally a "Jr."
Personally, I think it's arrogant on the father's part to allow such a naming unless you are a very noble or historically significant individual. Everything "Jr" accomplishes, the father will also get some derision of fame, simply by name association. Any failures, then the cliches begin, "You're just like your...,".
And because people who knew the elder first will always think of the Sr first, you get titles as a Jr that tend to add a "Y,or "IE," to the father's name. Don...Donnie, Ernest...Ernnie, Dave...Davey, Fred...Freddie. Worse yet, little Don, little Fred.
You take away that person's individuality and trust me, it's a life long fight to not be exactly like the Sr. Especially if unfavorable traits are associated with the name. To avoid being just like the father, Jr has to avoid possibly beneficial pursuits to not be "Just like..."
So, remember the person's life you're honoring in choosing the Suffix "Jr," could possibly be taking away a happy life from the younger.

Junior is sometimes further shortened to JR as a given name. I grew up with a boy named JR, and none other than Johnny Cash was born J.R. Cash but changed his name to John when enlisting, as the military would not accept initials as a first name.

The name Junior was given to 284 boys born in the US in 2016.
More than 99.9 percent of people with the first name Junior are male.

My husband's name is Junior. Most Samoans call their first born sons this. It has nothing to do with naming their child after them.