My answwer to similar question of one of my clients here in Slovenia:
What happens if the "SEO Title" is too long or longer than recommended number of characters? Does Google punish it? Or does the latter simply not show up? Are the words - “keywords” in the deleted (not shown) part taken into account in searches?
There is no Google penalty to penalize a site for having too long (or too short) an SEO title.
If the SEO address is too short, it simply means that you have not used all the space that Google makes available for the SEO address (which is, by the way, the most important CTR factor / decision maker whether Google users will click on your site or compete).
Google for SEO address (currently) allows approx. 65 characters (or limits the length of titles according to the length of pixels (according to the device in which it displays the SEO title).
If the SEO title is too long, Google cuts off the rest and displays 3 dots instead.
If “cut words” were considered as an SEO factor in the higher ranking of websites on Google, in theory we could “impose” thousands of keywords in the title, but this is a non-functioning and at the same time, old, “black hat SEO” tactic because Google, despite not displaying the full SEO title, when visiting the site, sees and reads the full title, and at the same time understands very well when the title (and everywhere else in terms of content) for these keyword stuffing.