"It will end badly" - 100%, but being early is the same as being too late.
The easiest way to stay on the right side of the market is simply the 200 Daily MA. If the market falls under, sell. If the market crosses above, buy. Of course you can combine that with a lot more TA and get really down into it, but for someone who doesn't want to know more, that is literally all you need to stay on the right side of the market. Everything else is just noise.
Will the above strategy get you the top? No. Will you pick the bottom? No. Will you make money in the long term? Yes. Same applies for any stock, look at the daily or weekly minimum.
The whole reason the market has rallied back so hard is because nobody believes in the rally, everybody is expecting is to fall over at any moment. The same was true in April, May, June, July, August now. I was fully in BBUS when we were around 2970 level, expecting it to roll over for obvious reasons, when that didn't happen I was confused for a solid month questioning everything about what I know and my decisions, turns out I was focusing on what was happening "now" instead of where this was all heading, i.e. lots more stimulus, negative rate, higher inflation etc...
There is a great channel on Youtube for anyone interested, Conquer Trading. It's all about TA and this guy has been spot on every turn. I highly suggest for those that want to learn more:
https://www.youtube.com/watch?v=uMfhhp5Fxy8
(20min delay)