First of all, they have made the process of getting the lvl 50 relic weapons quicker and easier in several ways. Yes, it used to be even grindier.
Secondly, of course it is going to feel grindy if you try to do it all at once. Don't spend so much time every day on it. Don't try to get it all done in a couple of days. Assume that it will take several weeks or even months before you are done.


Keep in mind that there are really only two reasons to get the lvl50 relic weapon. The first is to use it for cosmetic purposes. The second is for the personal satisfaction of having done it, once one is finished.
So if you think the process is too grindy, then don't do it. It is not like you will actually need the finished relic weapon.