It is not exhausting with the proper beliefs, but effortless, because the beliefs generate the thoughts and emotions. Forcing them with detrimental beliefs in place is exhausting.
Yes I heartily recommend changing the belief instead. Many times I’ve tried to force the positive attitude about something, even for weeks on end, and in one short 15 minute or so really deliberate introspective session realized I believed a silly thing, and completely transformed how I felt from then on. Yes it is definitely worth it.
You have to remember the core steps: do not identify with your beliefs/thoughts/emotions, you have them but you are not them, you can change them to your liking. Your beliefs are available, in the present, in the conscious mind - that is, the waking part of your mind you use every day, even though you may have formulated the belief (think about it like a judgement if that helps) minutes ago and are no longer thinking about it, it’s still there and accessible. Some may be invisible to you because you are thinking of them as facts of reality. Be on guard. Anything you think of as a fact is a belief. Simply be on guard to this and you will be able to see what you often see through. Seth calls these invisible beliefs, accessible but not noticed. You only have to be on guard, and they will become visible. And of course, finally, you can change these beliefs.
Incidentally, you change those beliefs by applying the deliberately / willfully forced imagination, thought and emotion mentioned earlier, except now you are aware of the belief and you are telling yourself, “this is not necessarily true even though I believe it”. You move thought in this way, you propel ideas. Change beliefs.
This repeats what I just said above, but you may find this post I wrote with exact steps for changing a belief helpful: Child stuck on fearful, anxious thoughts