You made a mistake and realized your error - forgive yourself, dust off your boots, and get back to work. You still have 8 solid years of saving ahead of you and this lesson, while expensive, can be made up for by a little extra earning and a little extra saving over time. Don’t beat yourself up, we all make mistakes.
I think step 1 is to have an allocation you can live with, that makes sense to you, that you aren’t going to make adjustments to for the next 6-8 years no matter what. Even if the market tanks another 50%. We can still be heading into a 80% down depression just as fast as we could be back at new highs. Wall Street is celebrating the buying opportunity while Main Street is preparing for the Great Depression 2. Who knows who will be right or when they will be right.
I have a rule - only sell stock when my bank account is empty, I have no cash, and I need to buy groceries. Otherwise I am in buy-only mode. The only time I would sell is to rebalance to my target allocation.
Now - about getting back in. I agree with others that you are asking about timing your repurchase after making the mistake of trying to time an exit/entry to the market. Only after you decide you will not sell again for at least 8 years, and what your allocation will look like during that period should you get back in. How you do it should be something that regardless of the results you will not continue to judge yourself for.
You could go 100% back in tomorrow and the market falls off a cliff and you have pie on your face twice. You could dollar cost average in and the market continues marching upward and you hurt your portfolio recovery even more. Maybe you split the difference and go 50% at once and then DCA the other half over a few months. You have to decide what you can live with if things don’t go the way you think they will.
The problem with DCA back in is you will be tempted to try to time every purchase waiting for the best day or hour or minute to click the buy button. I would only recommend DCA if you can automate it. Otherwise just lump it back in, the stress of timing a purchase every week is too much.
Your going to be alright either way. Best of luck.