Look for the Long Term Release (LTR) section. QGIS 3.28 was the primary LTR for a significant period; current LTRs may have updated to 3.34 or 3.44, but older versions remain accessible in the All Releases archive.
A: No. In fact, keeping multiple versions is recommended. Your projects saved in a newer version may not open in 3.28, so always keep an older LTR. qgis 328 link download
To summarize, the official and safest way to get the is: Look for the Long Term Release (LTR) section
To download QGIS 3.28, you can visit the official QGIS website: qgis 328 link download