Swiss Rail Pass assistance please

Hi, first time traveller to Switzerland this June, this is my itinerary, could you kindly advise what would be the best pass please?

21 June - Strasbourg to Interlaken - Murren (staying at Murren for 3 nights)
22 June - Murren
23 June - Murren
24 June - Leave Murren - Interlaken - Venice

Likely route or please advise if there is better
From Strasbourg - Basel - Spiez - Interlaken (21 June)
From Interlaken - Spiez - Milan - Venice (24 June)

Expecting travels to other parts within the area to eg Gridelwald, Jungfrau, Wengen, Gsteigwilore but will hike those within closer distance rather than trains etc, would you recommend a Swiss Pass or a Swiss Transfer pass? Also, wonder which leg it covers for the below:

From Strasbourg - Basel - Spiez - Interlaken (21 June)
From Interlaken - Spiez - Milan - Venice (24 June)

Eg: does it exclude every single leg listed here? or will I have to purchase some individually eg Strasbourg to Basel or Spiez to Milan to Venice. Help most appreciated!

Thank you,
Lina

Hi was attempting to purchase the swiss card at a local agency but was advised differently and thought to see your kind confirmation before I proceed further
Was advised every leg is charged 50% as opposed to having partnof inbound and oubound covered

Could you kindly advise on each leg below?

Inbound

Strasbourg - Basel (to purchase seperate ticket)

Basel - Spiez (covered free by swiss card or 50%?)

Spiez - Interlaken (covered free by swiss card or 50%?)

Interlaken - Murren (50% off with swiss card)

Outbound

Murren - Interlaken (50% by swiss card)

Interlaken - Domodossola (covered by swiss pass, 50% off, buy seperate ticket at full cost?) -> do you pass by Spiez? And is that covered?

Domodossola - Venice (buy seperate at full cost)

Could you also advise the best way to reserve tickets of for eg intercity trains as the website sometimes suggests parts of the ride are not available. Also, does Swiss card still offer 50% off to Jungrau compared to 25% at Swiss Pass? Apologies i had read quite a number of websites and am still confused.

Appreciate your guidance!

More familiar as well with Interlaken-brig/spiez - milan - venice. In this case does it cover me 100% until milan with swiss pass?

Hi Linac. The Swiss leg of your inbound trip (Basel-Mürren) will be for free with a Swiss Card. So will be the Swiss leg of your outbound trip (Mürren-Domodossola). On your remaining trips in Switzerland, including the Jungfraujoch, a 50% discount applies. Please refer to the Swiss Card page for all specifics and ordering options. Seat reservation indeed isn't necessary or even possible for most of the legs of your trip. Only international trains such as the one between Interlaken and Domodossola may need reservation, but that depends on the exact connection you choose. This FAQ and the seat reservation page provide further information.