Bell Labs had a simpler alternative in IFFE [0], that consisted of a single shell script [1]. You would specify any required headers, libraries and tests in a simple text file [2].
TypeORM is great and all - but it has its own quirks too and it's not a silver bullet.
In their case they would also maybe run into some issues as TypeORM has some initialization cost (building a model in memory when it first connects to the DB etc), some object mapping costs and other complexities (particularly around efficient query generation).
While there is nothing stopping it from working in a Lambda this would increase initialization time and cost which both matter since this is for a GraphQL API. I think the solution they've selected (Kysely) is probably a better fit.
ThePrimeagen did some benchmarks on stream recently - he found Bun to be slightly better in terms of average response time, but the biggest gain was P99 / P99.9 values under heavy load.
NodeJS seems to drop the ball on a handful of requests when it's getting slammed, i.e. upwards of 10s vs average of 100ms. Bun had a much smaller P50/P99 spread.
[1] https://akr.am/blog/posts/a-guide-to-compiling-programs-on-w...