A number of considerations:
Yes, a SSH server exposed to the Internet is going to be subject to incessant, large-scale brute-force attacks. At the very least you need some defense like Fail2ban or CSF-LFD. This will quickly ban offending IP addresses at firewall level.
Without this protection, and even if you have a strong password, your server will have to fend off the attacks, creating unnecessary load and waste of bandwidth. Think hundreds, maybe thousands of simultaneous attacks.
You can use a non-standard port for the SSH server, you will still get probes but fewer of them.
Maybe a better solution is to set up port knocking. The trick is to make the port open only to those who know the right combination.
If your home network has a static WAN IP address, then you could restrict the SSH server to predetermined, whitelisted hosts.
Another technique if you have a static/stable IP address is to do reverse SSH: instead of connecting to the server, let the server call 'home'. Use
autossh so that the connection is automatically restored between reboots or network outages.
However it seems to me that a VPN is a better alternative.
OpenVPN can run in UDP, or TCP, or both. I believe UDP is the default, and UDP is more difficult to scan (see nmap manual regarding UDP scanning), and most attacks focus on TCP services.
Which does not mean UDP cannot be a danger: just think of DNS or NTP reflection attacks.
Here you are, now you can combine several techniques, for example OpenVPN with port knocking and you have a setup that is quite stealth. If you don't want the hassle of installing a VPN and prefer to stick to the already-installed SSH the same steps can be used to protect your server.