The default chain for Let's Encrypt uses 2 intermediate certs in addition to your leaf (or server) cert. The ca.cer contains just the 2 intermediate certs. The fullchain.cer contains your leaf and the 2 intermediates. For Apache, it depends on your version which files you use. But, modern Apache versions use just the fullchain.crt and the private key file. See this too
You need to review Apache docs for configuring stapling. You then set the option for stapling in the cert although I don't know how in acme.sh off-hand.
Did you just add an AAAA record to your DNS? Because connections using IPv6 fail and that will prevent getting a cert since Let's Encrypt uses the AAAA IP address when present. You should correct your IPv6 routing or remove the AAAA record if not possible.
nslookup davemehler.com
A address : 66.228.47.34
AAAA Address: 2600:3c03::f03c:91ff:fedf:6fc
curl -I4 -m10 http://davemehler.com (4 uses IPv4)
HTTP/1.1 301 Moved Permanently
Date: Sun, 10 Jul 2022 12:16:11 GMT
Server: Apache
Location: https://davemehler.com/
(other headers omitted)
curl -I6 -m10 http://davemehler.com (6 uses IPv6)
curl: (28) Failed to connect to davemehler.com port 80 after 5002 ms: Connection timed out