This is the way. Just have an utterly hedonistic, fun, no-consequences day. Spend all your money having fun, whatever that means for you. Borrow a bunch of money to fund your exploits. No good or evil you do will be lasting (although, easing or causing suffering doesn’t have to be indelible to be ethically debatable).

Since Klnsfw’s method leaves 800–some bytes, you could add a list of things you’ve done as you go. Eliminate vowels to save space; in most cases this will still be understandable.

Skydv.scba grt brr rf.flyng lssns.HEROIN.

42 characters; you could fit a lot of activities into 800 characters. At some point, you start over from the beginning because, AFAYK, it’d be your first time anyway. Just start rotating the list, or just delete entries; if you come up with them again, it’s all the same.

I, personally, might allocate a few bytes to an iterator, because that would be interesting into to me. You could also use the count as a seed for a random number generator to ensure randomness in each loop. Actually, the more I think about it, an iterator might be the most valuable information: you could use it to generate a random activity for the period, and (with the bounds of what’s possible) ensure that you’re going something unique every time. Maybe one period you spend all your time and money feeding every homeless person in your city with an expensive meal.

Unlike Groundhog day, I’d never get bored, so I don’t think I’d ever be tempted to try to off myself to stop the loop.

I agree with you: this is almost like heaven. It really depends on how long the loop lasts - is it a day? OP implied it could be as long as a week, which would be better as you’d need that time to get anywhere in the world to do something, like spend some days at a high-end resort, or climb Kilimanjaro. Or source some drug you’d never otherwise try.

Finally, you might need space for DO NOT. Like, things you tried that didn’t go well.

Finally: someone was mocking the idea of compression. Why? You don’t have to decode it in your head; you only have to be able to transcribe it to and from a computer. Do the rules say I don’t have access to a computing device? OP didn’t stipulate that the bytes had to be ASCII.

I ran a test using words pulled from the American dictionary, cut at N bytes, and then run through smaz2. Using bisection, I was consistently able to encode 1470 ASCII characters into under 1024B; this adds 43% (446) bytes. 1024B isn’t a lot to type into a terminal and run through a decompression algorithm. Then you do the reverse at the end and just put byte by byte into the buffer.

The downside to this is it removes the advantage of being able to last-minute add a note to yourself to not do something. Like, unless you die instantly, you could do something like try to free-climb Half Dome, and when you slip, append: “N: Halfdome die”. You can always reformat it next time around to be more efficient.

Probably the best way would be to use compression, but always reserve 100 chars space at the end for a warning. Depending on the actual rules, and how the buffer functions, you might need to waste characters with cleartext notes:

smaz2:<bytes>
<100 character buffer for emergency note>

Otherwise, the uncompressed data would be in the format above.

To put it all together:

Uncompressed:

Check the time loop
Roll the tungsten D12
16XX53E324X14263E54
Iter: 0x7A92
Y: Skydv.scba grt brr rf.flyng lssns.heroin.
N: DMT.klmnjaro.swm w grt wht shrks.

That’s 156b. smaz2 brings it to 130b. Including EOL whitespace, 7B for the header, and 100B for the footer leaves 916B for data. That’s 1300 characters uncompressed. Again, depending on how the loop works, I might sacrifice some bytes to the header from the body to speed comprehension about what’s going on.