I need to upgrade Safari to access to my bank account but they are not updates available

Consider updating your bank instead.

Chase Bank is the only large financial institution clinging to an outdated and privacy-intrusive "user agent" query to determine browser requirements, which was always a bad idea. No other bank does that, and they don't seem to have problems with account security. Contact them and tell them to fix it or you will take your business elsewhere.

my bank says try chrome I dont like it.

Let me get this straight. They want you to install the most pervasive information-harvesting and -uploading system known to mankind on your Mac? To what end? That is the most egregiously irresponsible advice anyone could provide, and is more reason than ever to abandon that bank.

The workaround for end users who are unable to update their Macs to a newer macOS version is to use a different browser.

Consider Brave:

https://brave.com/

Firefox is a distant second choice:

https://www.mozilla.org/en-US/firefox/new/

The bottom line is that there is nothing wrong with your Mac's version of Safari, but that bank is using an outdated and ill-conceived method of determining browser requirements. If you are so motivated direct their attention to the WWW publication User-Agent Client Hints (courtesy VikingOSX).

In-depth background discussion here: chase wants me to update safari to 16, should I do that? - Apple Community

You know that you don't have to use any browser alternative all the time. You may not like Chrome, but you only need to fire it up to access your banking website. Otherwise, continue to use Safari for all of your normal day to day browsing. In fact, there's no reason you cannot have both open on the computer at the same time.

Of course, you may find one of the browsers suggested by Yer_Man in their post above to be more to your liking.

I am old too. The reality is technology advances and every entity involved with it either advances too or they fall behind and often can't catch up. Do you not want your bank to protect you accounts as far as possible? That's the alternative to not updating security.

Use Firefox or Brave browser.

Firefox

Brave

VIvaldi

Try those.

My guess is you're a Chase bank customer? I've seen quite a few complaints in these forums from Chase customers. In my mind, their web developer took shortcuts when coding their website.