Sona

Sona has no dash and 530 base HP at level 1 — Rocket Grab (Q) lands once and either Sona or her AD carry dies before Crescendo (R) is online. Power Fist (E) knock-up chains for a guaranteed Static Field (R) silence-burst before Aria of Perseverance (W) can cast.

Sona has no stun pre-6 — Crescendo (R) needs setup time Focused Resolve (W) interrupts. Mantra-Q cone burst out-trades Power Chord (P) procs, and Inspire (E) shield-speed combo nullifies Aria of Perseverance (W) shield healing on the ADC.

Sona has no stun pre-6 — Crescendo (R) is the only CC, easily dodged by Eclipse (W) damage reduction. Aria of Perseverance (W) shield breaks under Shield of Daybreak (Q) plus Sunlight (P) burst, and Power Chord (P) procs cannot save her from Zenith Blade (E) root.

Sona has no hard crowd control to interrupt Shield Vault's W dash until level 6, and Crescendo R is a slow skillshot Pantheon sidesteps with E movement. Aria of Perseverance heal cannot outpace W stun plus Comet Spear tap damage,

Sona has no dash to break Pyke's Ghostwater Dive approach, and Aria of Perseverance heal cannot outpace Bone Skewer pull plus Phantom Undertow stun chain. Crescendo R is a slow skillshot Pyke dodges with W invisibility,

Sona has no dash and Crescendo R is a slow skillshot that fires too late after Grand Entrance lands. Aria of Perseverance heal cannot outpace Battle Dance dive damage, and Power Chord stun cannot fire faster than The Quickness charm window during the engage.

Sona has no stun or knock-up to interrupt Ferromancy: Crash Down landing on her ADC until Crescendo R at level 6 — and Crescendo is a slow skillshot Rell sidesteps. Aria of Perseverance heal cannot outpace the Crash Down knock-up plus Full Tilt chain damage,

Sona has no dash and her Crescendo R is a chain-stun that needs vision on a clumped group. A Death Sentence Q hook from lantern range cancels her R channel mid-cast, Power Chord passive stack burst cannot reach Thresh through Flay E knock-back,

Sona Hymn of Valor (Q) 850 range falls short of Vel'Koz Plasma Fission (Q) 1050 range, so she eats Q poke every wave. She has no hard CC pre-6 to peel Tectonic Disruption (E) knock-up on her ADC and Power Chord passive damage cannot match Organic Deconstruction true damage burst.

You and Me! (W) attached untargetable state denies Hymn of Valor (Q) poke on the carry, and Final Chapter (R) wave snares stun Sona mid Crescendo (R) channel. Zoomies (E) ally speed plus heal out-paces Aria of Perseverance (W) throughput.

Sona has no stun or knockup outside Crescendo R, which is a long skillshot Zac dodges by E charge re-aim. Aria of Perseverance W shield is short-range, and Song of Celerity E movement speed cannot escape the chain into Let's Bounce! R before R locks her down.

Living Shadow (W) plus Death Mark (R) double-dash delete Sona before Aria of Perseverance (W) can complete the cast animation. She has no Zhonya's-style escape baseline and the 1.5s Crescendo (R) windup is too long to interrupt his gap-close.