Under a Protestant perspective what sort of ‘sacrifices’ as a symbolic priest can a believer perform within the ‘priesthood’ of all believers? In 1 Peter believers are represented as a Priesthood that 'offer spiritual sacrifices'. Assuming that they can't be for expiation as only Christ was worthy to offer his own soul for that (represented by animal blood in the OT) what sort of sacrifices are these?:

As you come to him, a living stone rejected by men but in the sight of God chosen and precious, you yourselves like living stones are being built up as a spiritual house, to be a holy priesthood, to offer spiritual sacrifices acceptable to God through Jesus Christ. (ESV, 1 Peter 2:4-5)

Note: I used a technical word that seems to require a definition.
Expiation definition
Guilt is said to be expiated when it is visited with punishment falling on a substitute. Expiation is made for our sins when they are punished not in ourselves but in another who consents to stand in our room. It is that by which reconciliation is effected. Sin is thus said to be &quot;covered&quot; by vicarious satisfaction. The cover or lid of the ark is termed in the LXX. hilasterion, that which covered or shut out the claims and demands of the law against the sins of God's people, whereby he became &quot;propitious&quot; to them. The idea of vicarious expiation runs through the whole Old Testament system of sacrifices. (Bible Dictionary)
The best place to look for an answer to how Lutherans would view the 1 Peter passage on sacrifices is to look at the section on the Defense of the Augsburg Confession on sacrifice.

19] Moreover, the proximate species of sacrifice are two, and there are no more. One is the propitiatory sacrifice, i.e., a work which makes satisfaction for guilt and punishment, i.e., one that reconciles God, or appeases God's wrath, or which merits the remission of sins for others. The other species is the eucharistic sacrifice, which does not merit the remission of sins or reconciliation, but is rendered by those who have been reconciled, in order that we may give thanks or return gratitude for the remission of sins that has been received, or for other benefits received.
25] Now the rest are eucharistic sacrifices, which are called sacrifices of praise, Lev. 3:1f.; 7:11f.; Ps. 56:12f., namely, the preaching of the Gospel, faith, prayer, thanksgiving, confession, the afflictions of saints, yea, all good works of saints. These sacrifices are not satisfactions for those making them, or applicable on behalf of others, so as to merit for these, ex opere operato, the remission of sins or reconciliation. For they are made by those who have been reconciled. 26] And such are the sacrifices of the New Testament, as Peter teaches, 1 Pet. 2:5: An holy priesthood, to offer up spiritual sacrifices. Spiritual sacrifices, however, are contrasted not only with those of cattle, but even with human works offered ex opere operato, because spiritual refers to the movements of the Holy Ghost in us. Paul teaches the same thing Rom. 12:1: Present your bodies a living sacrifice, holy, acceptable, which is your reasonable service. Reasonable service signifies, however, a service in which God is known, and apprehended by the mind, as happens in the movements of fear and trust towards God. Therefore it is opposed not only to the Levitical service, in which cattle are slain, but also to a service in which a work is imagined to be offered ex opere operato, The Epistle to the Hebrews 13:15, teaches the same thing: By Him, therefore, let us offer the sacrifice of praise to God continually; and he adds the interpretation, that is, the fruit of our lips, giving thanks to His name. He bids us offer praises, i.e., prayer, thanksgiving, confession, and the like. These avail not ex opere operato, but on account of faith. This is taught by the clause: By Him let us offer, i.e., by faith in Christ.