A real notebook and pen are the perfect tools for this. Its the only one I know that works, long term.
append only log works, but skimming through 2 months of logs for a specific thing is poor and slow but very useful. I don't do that often but when i do need it sometimes and especially fast, like on a call, with no lead time. Its a superpower.
I now organize my notebook a with a few conventions that make it more useful.
I limit myself to using only the right side of a page for logs from whole week. Each new week gets a new page, always on the right side. Put the date as the page header. Makes skimming easier. Put any important tasks / targets for the week right after.
Further Split right page into 3 columns. First 2 for work logs, third column for recurring weekly/biweekly meeting stuff. Very easy to go back to what was discussed 2 months ago. All logs are usually 1-3 words. Just cues. but everything has a topic subheader.
Left page is free form for detailed stuff. Things i discover, design, 1:1 meeting notes, questions i need answers to, philosophy, anything new on HN, etc. Right page serves as context.
I also do an index on the first page of the book pointing to anything that i find repeatedly useful. Could do page numbers but i put the date as its naturally ordered by the dates on the right page.
Been doing this a while and works perfect. I have everything I need in one notebook, i can carry it with me. a $1 composition book with 50 pages lasts well over six months.