Question

Hello Rabbi, I saw that two years ago the Rabbi answered someone who asked about parts of the prayer that are not obligatory, that although there are indeed parts that are not obligatory, custom makes them binding. My question is this: I find the length of Pesukei DeZimra very difficult, and also some of the concluding parts of the prayer that the Rabbi noted are not necessarily obligatory. The question is whether there really is a full obligation for all of it on the basis of custom, and whether it is worth investing every effort in the matter and struggling through every chapter of Pesukei DeZimra (of course, if that is the answer, that is what I will do—or at least try as much as I can…), or perhaps the obligation created by custom is weaker for some parts, or perhaps one can do annulment of vows regarding this? Thank you very much!