Yes, Concept 1 is absolutely possible in Odoo 14, though it takes some setup. You can keep a single warehouse and create separate internal locations for each workstation (WS1, WS2, etc.). Then, use reordering rules and routes so each workstation automatically gets replenished from the main storage when its stock runs low.

For manufacturing, you can configure pull rules so each workstation only uses materials from its own location, and define where finished products should be stored after production.

If you’re just starting with Odoo, Concept 2 (treating each workstation as its own warehouse) might seem easier, but it can quickly complicate reporting and inventory tracking. Concept 1 is cleaner long term once you understand routes and replenishment.

Routes, putaway rules and removal strategy is already support well enough to setup warehouse with many sub-locations of WH/Stock, and one or some product items (1-5 items) maybe stored in a specific sub location, on the purchase-receive and sales-delivery odoo already choose the sub location to store to or from sub location to pick/deliver from. In case of interwarehouse transfer with many sub location something like 1000, it is already not practical, because will need too many routes/rules needed.

Is there a practical way to make odoo can select the right sub-location per product in picking lines to suply interwarehouse transfer out like it was in sales delivery picking?

Yes Concept 1 is quite possible if the assumption is that an MO would be completed in only 1 work center (workstation). While in Odoo a work center is assigned based on work order operation and multiple work centers can be utilized in completing 1 MO.

In V14, on the miscellaneous tab of an MO you can provide the component location and location of finished product prior to confirming the MO.

If more granular inventory transfer operations are required, it can be achieved by activating 3 step manufacturing route from Inventory > Configuration > Warehouse

Below tutorial details the process

https://www.odoo.com/slides/slide/manufacturing-in-two-or-three-steps-2804?fullscreen=1

Replenishing stock at a storage location is possible by defining min, max and multiple qty for a product at the specific location. Trigger can be manual or auto and the replenishment route can also be selected. (transfer from main stock, or buy etc)

Inventory > Operations > Replenishment

As detailed by @Lars Aam

Concept 2 - No don't.  A warehouse is a physical area with a fence around (normally) and it got an adress. So unless there are several adresses, do not create several warehouses.  

Whenever you manage warehouses and locations, alwasy configure at according to the physical layout. 

Concept 1: Yes this can be done with standard configuration. But it is a little tricky.  I tried to test a little. And came up with:

Divide your warehouse into two virtual location (You configure the locations as type View).  One of these are for manufaturing components.  You will a top internal location that can have stock (Let us name it Prod Area), and below that you set up your location for WS1 - WS4.  Manufacturing operation must have source location = Prod Area.  

When you create your manufacturing order, it will look for components in Prod Area and the sub location you have below. 

The View type Location is the header for all - let me call it General storage.  Under there you will have all your locations for storage of whatever.  This might also be the area for Destination location for the manufacturing operation.  You can use Put Away rules for how to find the best location for storage of finished production.

Replenish to WS1 - WS4:

Create a route like this:

The rules is what does the trick and set up like this:

 On the prooducts you want to refill from storage to work center you select also the route Refill.  And then create a reordering rule like this:

One rule that say I will buy it and store in General Storage, and Min qty in stock = 500

Other rule say I will have min 10 in location WS1 (which is the one with Work center 1) and use the route Refill. Running either the Scheduler or if you use the Replenishement, will create an internal transfer to fill up the location.

I hope this helps you on the way.