"Server closed the connection unexpectedly" when installing PostGis on OS X with M1 chip - postgresql

Question

I am attempting to install Postgis on my newly created Postgresql DB and am running into issues doing so.
Environment
OS X (Big Sur, 11.2.3 with a M1 chip)
Postgresql version: stable 14.3, installed with homebrew (more precisely, with the following syntax: arch -arm64 brew install postgresql)
Postgis version: stable 3.2.1, installed with homebrew (same)
What I'm trying to do
I want to install postgis on my postgresql database as such.
Christophers-MacBook-Air:postgres root# psql -U chrisneve -d mydbname
psql (14.3)
Type "help" for help.
mydbname=# create extension postgis;
The problem
The above snippet generates this error.
mydbname=# create extension postgis;
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!?>
Before trying with psql directly, I executed the same command using DataGrip, which generated this error. (I also tried with the "cascade" mode: create extension postgis cascade, which generated the same result).
mydbname.public> create extension postgis
[2022-05-28 10:55:30] An I/O error occurred while sending to the backend.
[2022-05-28 10:55:30] Unrecoverable error received, the connection is spoiled
DataGrip also displayed a popup-style error saying this.
Error [57P03]: FATAL: the database system is in recovery mode
What I tried
I initially didn't know exactly where the error lied, so I started by asserting that the problem wasn't with the creation of extensions (for whatever reason).
select * from mydbname.pg_catalog.pg_extension
drop extension plpgsql
create extension plpgsql
This worked just fine; other extensions load fine.
Realising the issue seemed to come from Postgis, I tried removing and reinstalling Postgis, and even Postgresql, with homebrew, multiple times. It changed nothing.
I then wanted to install Postgis from a different location of https://postgis.net/install/#binary-installers for OS X, but all other install mechanisms (other than homebrew) told me not to mix with other installations, so I didn't try them.
FWIW, I installed Postgis in the past on an identical DB on a Windows machine, so although I'm no Postgis expert I do know the install process.
It would be much appreciated if a Postgis maintainer could help me out with this. Is this a new bug with the M1 chips? I can provide logs if it helps.
Many thanks,
Chris