S3 download performance degraded since last boto3 update

I've been using the python library boto3 for a long time in one of my services to download files (0.25 to 2 MiB in size) from S3. A few days ago I noticed that the speed with which I am able to download from S3 got worse after upgrading to the most recent versions of boto3 and awscli. After reverting back to the version I was using before, the download-speed returned to normal.

The affected libraries seem to be (working version => slower version):

awscli                 1.25.95 => 1.27.30
boto3                  1.24.94 => 1.26.30
botocore               1.27.94 => 1.29.30

I am using the python boto3 function download_fileobj to download files from my S3-bucket, which on average takes 140ms for a download, but requires 160 to 180ms in the newer library version. The cli-tool (e.g. aws s3api get-object --bucket=my-bucket --key=8cff98a2-12408077 /dev/null) also now needs on average 820ms to complete. With the older version it's only 750ms.

Is this a know issue or has something changed which I should update in the way I am using the S3-client?