Workaround for OpenVPN no automatic authentication available?

The last OpenVPN 2.5.3 linked to OpenWRT 21.02.2 does not allow automatic authentication:

Mon May 16 06:58:41 2022 daemon.notice openvpn(USAtun)[8004]: OpenVPN 2.5.3 mips-openwrt-linux-gnu [SSL (OpenSSL)] [LZO] [LZ4] [EPOLL] [MH/PKTINFO] [AEAD]
Mon May 16 06:58:41 2022 daemon.notice openvpn(USAtun)[8004]: library versions: OpenSSL 1.1.1n  15 Mar 2022, LZO 2.10
Mon May 16 06:58:41 2022 daemon.err openvpn(USAtun)[8004]: neither stdin nor stderr are a tty device and you have neither a controlling tty nor systemd - can't ask for 'Enter Auth Username:'.  If you used --daemon, you need to use --askpass to make passphrase-protected keys work, and you can not use --auth-nocache.
Mon May 16 06:58:41 2022 daemon.notice openvpn(USAtun)[8004]: Exiting due to fatal error

due to security reason.
Do we have a workaround?
Hereinafter the configuration:

client
dev tun0
proto udp
nobind
ns-cert-type server
persist-key
persist-tun
reneg-sec 0
dhcp-option DNS 8.8.8.8
dhcp-option DNS 8.8.4.4
redirect-gateway
verb 5
auth-user-pass
ca CACertificate.crt
cert UserCertificate.crt
key PrivateKey.key
remote us.lazerpenguin.com 443
cipher AES-256-GCM
auth SHA256