I solved the problem for myself by commenting out the problematic lines.
# OpenVPN for Surfshark
client
dev tun
proto udp
setenv FRIENDLY_NAME "Surfshark VPN: United Kingdom, London"
remote uk-lon.prod.surfshark.com 1194
#resolv-retry infinite
remote-random
nobind
tun-mtu 1500
#tun-mtu-extra 32
mssfix 1450
#persist-key
#persist-tun
ping 15
ping-restart 0
#ping-timer-rem
reneg-sec 0
remote-cert-tls server
<auth-user-pass>
login
password
</auth-user-pass>
#comp-lzo
verb 3
#pull
fast-io
cipher AES-256-CBC
#data-ciphers AES-256-GCM:AES-256-CBC
#data-ciphers-fallback AES-256-CBC
auth SHA512
<ca>
xxx
</ca>
key-direction 1
<tls-auth>
xxx
</tls-auth>
