This is what my ideal squad in the 2021-23 time period would look like keeping in mind the ODI World Cup, World Test Championship, and 2 World T20s.
Key:
/ -> backup or develop for that role
Tests:
1. Shan Masood
2. Abid Ali/Imam/Abdullah Shafiq/Omair bin Yousuf
3. Haider Ali/Omair bin Yousuf/Imran Butt
4. Babar Azam
5. Saud Shakeel/Hassan Mohsin/Abdul Wahid Bangalzai
6. Rizwan
7. Shadab Khan/Zafar Gohar (2nd spin-bowling AR in subcontinent/A pace-bowling allrounder overseas for God's sake)
8. Zahid Mahmood/Yasir Shah/Faisal Akram (if Zahid and Yasir are too old, back the young Faisal Akram)
9. Shaheen Afridi (rest him in the not-so-important series to manage his workload)
10. Abbas/Ahmed Bashir
11. Naseem Shah/Musa Khan/Akif Javed
Rizwan, Masood, Babar, Abbas, and probably Yasir will be the most experienced players, and youngsters like Haider, Omair, Naseem will help form a versatile lineup.
ODIs:
1. Imam/Abdullah Shafiq/Omair bin Yousuf
2. Haider Ali/ any other dynamic opener (maybe Fakhar if he improves)
3. Babar Azam
4. Rizwan/ Rohail
(on flat decks Rohail should be the go-to-man courtesy of his improvisation)
5. Saud Shakeel/Qasim Akram/Shadab (the Hafeez/Shoaib Malik role)
6. Shadab Khan/ Hassan Mohsin (Shadab has to play, be it at #5 or #6)
7. Khushdil Shah/Hussain Talat
8. Zafar Gohar/ Faisal Akram (considering the WC is in India, we'll need a proper spinner who can spin the ball well)
9. Shaheen Afridi (rest him in the not-so-important series to manage his workload)
10. Rauf/Hasnain/Musa Khan/Naseem Shah (if he stays fit)
11. Wahab/Amir/Hassan Ali (need a bit of bowling experience in the WC too)
Strong batting till #8 with 4 pace bowling options and 3 spin options. Babar to anchor the innings while Haider, Rohail, Shadab, Hassan Mohsin, Khushdil, and Talat have the power-hitting prowess.
T20Is:
1. Babar Azam
2. Abdullah Shafiq/Zeeshan Malik
3. Haider Ali
4. Hafeez/Danish Aziz/Hassan Mohsin
5. Shadab Khan (VC)
6. Rohail Nazir/Azam Khan
7. Khushdil Shah/Hussain Talat
8. Zafar Gohar/Faisal Akram/Ammad Butt (4th pace bowling option if the need be)
9. Shaheen Afridi (rest him in the not-so-important series to manage his workload)
10. Wahab Riaz/Amir/Rauf
11. Rauf/Hasnain/Musa Khan
3 spinners, 3 pacers, and strong aggressive batting till #8.
I spent a lot of time on this, so feel free to add your suggestions.