Deleting incremental backups created with rsync and symbolic links: recursive effect?

Question

I am doing incremental backup according to the following example found there: https://linuxconfig.org/how-to-create-incremental-backups-using-rsync-on-linux

#!/bin/bash

# A script to perform incremental backups using rsync

set -o errexit
set -o nounset
set -o pipefail

readonly SOURCE_DIR="${HOME}"
readonly BACKUP_DIR="/mnt/data/backups"
readonly DATETIME="$(date '+%Y-%m-%d_%H:%M:%S')"
readonly BACKUP_PATH="${BACKUP_DIR}/${DATETIME}"
readonly LATEST_LINK="${BACKUP_DIR}/latest"

mkdir -p "${BACKUP_DIR}"

rsync -av --delete \
  "${SOURCE_DIR}/" \
  --link-dest "${LATEST_LINK}" \
  --exclude=".cache" \
  "${BACKUP_PATH}"

rm -rf "${LATEST_LINK}"
ln -s "${BACKUP_PATH}" "${LATEST_LINK}"

After a few incremental backup This gives me a list of folder like this:

dir
dir_2024_06_21T18_17_40
dir_2024_06_21T18_18_14
dir_2024_06_21T18_18_32
dir_2024_06_21T18_18_50
dir_latest

After a while with enough changes, the disk will becomes full

I have the following questions:

1. If a file thefile was created between dir_2024_06_21T18_18_14 and dir_2024_06_21T18_18_32 and I delete dir_2024_06_21T18_18_32, is thefile going te be still found in dir_2024_06_21T18_18_50 or not (because there is some kind of recursive reference in the time) or can I safely delete dir_2024_06_21T18_18_32 and still find thefile in dir_2024_06_21T18_18_50?

2. More generally, is there a better strategy to erase the incremental backups when the backup disk becomes full?