Start out with a reward in mind
If you know you have something to look forward to, the whole thing won’t be so daunting. Maybe there is a piece of artwork you have been eyeing, or there are some pictures that need to be framed and hung.
Have too much stuff already? Take 3 of your least favorite items in each room, and give it to a local shelter or donation organization. Then take the rest of your stuff and re-decorate! Take your artwork that is in your room, and put it in the living room. Or take some of the fireplace decor and put it in the bedroom. It will feel like you went to the store and bought all new stuff, without the lingering credit card debt at the end of the month.
If the deep cleaning part is still haunting you, bring a friend over, and make it into a dance party. You remember how easy it was to clean your room when you were a kid and your BFF was over. Plus a few drinks and music can make anything better!