Is there any way to show active subscription plan on stripe's embeddable table, like passing customer, subscription or price id?
https://stripe.com/docs/payments/checkout/pricing-table
How on client side, where stripe pricing table is used, can be prevented for user/customer to select another (or same) plan and do any sort of action except updating current plan with upgrade or downgrade?
The pricing table product is built for first time purchases and it allows you to easily drop an iframe on your webpage that shows the different price options that you offer to your new customers. Once you have a Customer that has already made a purchase, the pricing table product is not what should be used.
Instead, separately, you can let your existing customers manage their subscriptions with the Customer Portal here which has a full Stripe redirect page. You can pass the list of Price ids when creating the portal configuration so your customers are able to upgrade or downgrade to different prices.