While you remain on a Vegas Pro subscription arrangement, you already get updates and upgrades (an upgrade is to the next version of Vegas Pro - at this time, there is no later version of Vegas Pro than version 23).
If you are wanting to get a lifetime version of Vegas Pro 23, you may be eligible for upgrade pricing if you have a previous version of Vegas Pro (i.e. Vegas Pro 22 or earlier) that was purchased outright, not under the subscription model. If you don't have an earlier 'purchased' Vegas Pro version then, according to Vegas staff advice earlier this year on this forum, upgrade pricing is not available going from subscription to a lifetime purchase.
I am not on the sales side of the company, but I believe users with an annual subscription do qualify for the upgrade price for a lifetime license.
If you renew your subscription, the application will again be available for one year, which will include all updates and and upgrades during that one year time period.